[EdZ]

The reason why the throwaway pitch works I think (not sure if this has been explained) it because you can use a fuller swing (more swingspeed)...for more spin.....

....and the compression loss from the throwaway makes is so the ball lands soft on the green. (higher trajectory...less forward momentum when the ball lands)

more spin + higher loft

I like to think of it almost as taking a shaving off the ball.

A 'throw away' pitch can certainly be useful, but you can generate massive spin and very high trajectory with a full, agressive motion, given a proper setup

A very open stance and a very open clubface (clubface very nearly to target) - the key is a ball position that 'matches' the amount of open you are (stance and clubface combination)

Relative to your stance line, there should be NO throw away and a forward leaning, hands ahead, DOWNward impact with a flat left wrist.

This will produce a ton of backspin, and a fair bit of side spin so plan accordingly. Off hardpan you can get 'silly spin' even with a square setup - get those hands ahead and hit down